It is conventional practice to empty trash containers into the open-top, trash-receiving body of a trash pick-up truck by means of an automatically operable mechanism attached to the truck alongside the body. This equipment is used extensively in cities where residences and possibly at least certain commercial and industrial establishments are provided by the municipality with relatively large trash containers of uniform size and shape. Periodically, usually about once a week, the residences and other establishments place their trash containers in a suitable location, as at curb-side or in an alley, and the truck is driven from one trash container to the next. As the truck stops at each trash container, the mechanism moves laterally away from the truck, picks up the container, then retracts to its normal position alongside the truck and swings the container upwardly to an upside down position over the trash receiving body so that the trash in the container falls by gravity into the body. These motions are then repeated in reverse order to return the empty container to its original location.
The loaded trash containers frequently are heavy and the mechanism used to dump the containers are subject to great stress and abuse in use, with the result that they heretofore have required frequent servicing and repair which means that the trucks themselves are often out of service sometimes for extensive periods of time. For the most part, these dump mechanisms have been operated by a multiplicity of hydraulic cylinders which are controlled by valves in the hydraulic circuits that served the cylinders and the valves in turn are energized by limit switches disposed at strategic locations as required to limit travel of the various moving parts of the equipment. The apparatus necessarily must operate rapidly so that, in addition to the physical abuse to which the moving parts of the apparatus are subjected in use, the numerous power cylinders and valves are subject to frequent breakdowns and the limit switches require frequent repositioning and adjustment and not infrequently they are damaged to such an extent not only by physical abuse but also by weather and other environmental conditions to which they are exposed, that they cannot be repaired but must be replaced by new parts.